Method and apparatus for use in making valve protector caps for compressed gas cylinders



Oct. 19, 1954 Filed; March 31, 1952 D. M. ROCKWELL, JR METHOD AND APPARATUS FOR USE IN MAKING VALVE PROTECTOR CAPS FOR COMPRESSED GAS CYLINDERS v 2 Sheets-Sheet l I'NVENTOR.

M. ROCKWELL, JR 2,691,818

METHOD AND ARPARATUS FOR USE IN MAKING VALVE PROTECTOR CAPS FOR COMPRESSED GAS CYLINDERS Filed March 31, 1952 Oct. 19, 1954 2 Sheets-Sheet 2 I I l 42 65 a 36 l i l I 27 I I i I I I Z I I I l I I l l I I I I i i 37 I I i 32 I I l l 25 I I I 1 I I I I l I I INVENTOR.

Patented Oct. 19, 1954 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR USE IN MAKING VALVE PROTECTOR CAPS FOR COMPRESSED GAS CYLINDERS Dean M. Rockwell, Jr., Buffalo, N. Y.

Application March 31, 1952, Serial No. 279,586

Claims. 1

This invention relates to improvements in valve protector caps of the type commonly used in connection with compressed gas cylinders to cover and protect the valves of such cylinders from damage due to shipping or handling of the same.

One of the objects of this invention is to provide a novel and improved method for use in forming these caps.

Another object is to provide a method by means of which these caps can be readily formed by spinning the same from tubular metal while hot and then closing, by means of a plug, the axial opening left from spinning.

A further object is to provide improved means for positioning a plug in the crown portion of the cap to close the opening left therein after spinning.

A further object is to provide an improved method and apparatus for inserting a plug in the crown of the valve cap while the same is hot by using the plug while cold to form an aperture in the cap into which the plug fits, whereby the plug will be tightly gripped in the newly formed aperture when the cap shrinks due to cooling of the same.

Another object is to provide mechanism by means of which a plug may be rapidly inserted into the crown of the cap immediately following the spinning of the cap.

Other objects and advantages will be apparent from the following description of someembodiments of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. 1 is a side elevation of the upper portion of a compressed gas cylinder having a cap embodying this invention applied thereto.

Fig. 2 is a central sectional view of a piece of metal tubing from which the cap is spun.

Fig. 3 shows a longitudinal, sectional view of a cap after the spinning operation has been completed.

Fig. 4 is a top plan view thereof.

Figs. 5 and 6 are central, sectional elevations of an apparatus for use in inserting the plug into the crown of the cap, Fig. 5 showing the parts in the positions which they occupy prior to placing the plug in the cap, and Fig. 6 showing the parts in the position which they occupy when the plug has been positioned in the cap.

Fig. 7 is a fragmentary, longitudinal, central sectional elevation of the crown portion of the cap on an enlarged scale showing the plug in its operative position therein.

In Fig. 1, I0 represents a compressed gas cylinder of the type commonly employed for the transport and storage of gases at high pressures. These cylinders are provided at their upper ends with valves of any suitable kind (not shown) for controlling the admission and discharge of compressed gas into and out of the cylinder. These valves are rather easily damaged by impacts or blows to which they may be subjected during shipment of the cylinders or, for example, in case the cylinders fall, or if the valves come into contact with foreign objects. Frequently, these cylinders contain poisonous or injurious gases and, consequently, every possible precaution should be taken to prevent damage to the valves. Hence, caps are ordinarily employed which may be removably secured to the upper end of the cylinders so as to extend about the valves and protect the same against damage. II in Fig. 1 represents a cap of this type embodying my invention.

In accordance with this invention, the caps are formed from tubing which is cut to the required length and subjected to a spinning operation to partially close one end to form the crown of the cap. M, Fig. 2, shows a length of tubing which may be used for the forming of a cap, and Fig. 3 shows the same tubing after it has been subjected to a spinning operation to form the crown l5 of the cap. This spinning is generally done while the end of the tube to be spun is raised to a relatively high heat at which the metal of the tube is quite soft and pliable. The spinning may be eifected by means of any suitable or well known apparatus.

Due to the manner in which the spinning is performed, the crown portion of the cap is of gradually increasing thickness from the periphery to the axial portions of the crown, this being particularly desirable for the reason that the crown portions of the cap are most important for protecting the valves and generally receive the severest blows or impacts. The body portion I 6 of the cap is not changed by the spinning operation and remains substantially of the same diameter and thickness as the original length of accordance with my invention by means of a cold plug which can be used for the dual purpose of acting as a punching tool for punching out a quantity of metal around the aperture II. This punching can be easily effected by means of the plug itself which, because of its cold condition is of course very much harder than the hot metal of the crown of the cap. The plug is then left in the aperture formed thereby, and when the hot metal of the crown of the cap cools, it contracts, and thus very securely grips the plug to hold the same in the opening formed thereby. The operation of inserting a plug in the crown of the cap can most effectively be done immediately after the spinning of the cap while hot, since a reheating of the cap is thereby rendered unnecessary.

In Figs. 5 to '7 I have shown a plug 20 of a type which can be successfully used for closing the opening in the top of the cap. This plug as illustrated by way of example, includes a substantially cylindrical lower part 2 l, the outer or side edges of which are preferably arranged at an angle to the lower face of the plug so that they will readily cut through the soft, hot metal of the cap. The plug is also preferably provided at its upper end with an enlarged, outwardly extending, annular flange 22 which acts somewhat as a stop to limit the movement of the plug relatively to the crown of the cap, and the lower face of which, when the plug is in its final operative position, extends substantially flush with the outer surface of the crown of the cap. Immediately between the inner cylindrical portion 23 and the flange 22, the plug is preferably undercut to slightly smaller diameter than the flange at, such undercut portion being shown at 24, Fig. 7. This undercut portion is not absolutely necessary, since if the body portion of the plug is made of truly cylindrical form from the inner face thereof to the flange 22, the cooling of the metal at the crown of the cap will cause the same to contract slightly and firmly grip the body portion of the plug. However, by providing this body portion with an undercut, annular, outer surface, a more secure gripping of the plug by the contracting metal is assured since the metal of the crown on contracting will be forced into the undercut part of the plug.

Any suitable or desired means may be provided for inserting the plug into the crown portion of the cap, and in the construction illustrated in Figs. 5 and 6, I have provided a die 21 of substantially tubular form over which the cap immediately after the spinning operation, may be positioned, as clearly shown in Figs. 5 and 6. This die may be mounted on any suitable base or support 28 which is provided with an aperture coinciding with the inner bore or passage 29 of the die so that slugs of metal cut from the cap may readily be discharged from the die. The upper portion 36 of the die may he formed in any suitable or usual manner to fit into the interior of the crown of the cap.

Any suitable or desired means may be provided for guiding the cap into correct relation to the die 21. For example, the base 28 of the die may be provided with a pair of upwardly extending posts 35 and 32 which are so spaced relatively to each other and to the die that if the cap is lowered to telescope over the die 2'! and is pushed into engagement with the posts 3! and 32, the cap will be in correct relation to the die.

The positioning of the plug in the cap may be effected by means of a plunger or punch of any suitable or desired construction, and this punch is preferably also provided with means for releasably holding the plug until the same is positioned in the crown of the cap. In the construction shown for this purpose in Figs. 5 and 6, 35 represents a punch or plunger which may be mounted in any suitable manner on a reciprocating part 36 of a press of any suitable or desired type. The punch is preferably provided on the lower portion thereof with a plug holding sleeve 38 slidably mounted on the punch. In the particular construction shown, the punch may be provided on the outer surface thereof with a slot Or keyway 39 into which a part of the guide pin 38 may extend to hold the plug supporting sleeve 38 in correct relation to the punch. Any other suitable means may be provided for releasably holding the sleeve on the punch. 42 represents a coil spring extending about the punch 35 and yieldingly bearing downwardly on the plug supporting sleeve 38 to normally hold the same in the position shown in Fig. 5, in which position a plug may be positioned in holding relation on the sleeve.

The lower end of the plug supporting sleeve 38 may be provided with means of any suitable or desired construction for releasably gripping a plug 29. In the construction shown for this purpose, the lower end of the plug supporting sleeve 35 is provided with a plurality of spring pressed detents M arranged in radially extending apertures in the lower part of the sleeve.

These detents may be in the form of balls pressed toward the axis of the punch by means of springs 35. When a plug is pushed upwardly into the recess at the bottom of the plug holding sleeve 38 below the plunger or punch 35, it will be yieldingly held by the detent M. Any other means for holding the plug on the sleeve 38 in position to be acted upon by the plunger 35 may be employed. The spring 32 cooperating with the guide pin it normally holds the sleeve 38 in the position shown in Fig. 5, in which the sleeve extends sufliciently below the bottom of the punch or plunger 35 so as to provide ample room for the insertion of the plug into the sleeve. When the plunger is depressed to force the plug through the crown of the cap into the position shown in Fig. 6, the sleeve 38, upon contacting with the cap, stops its downward motion, resulting in compression of the spring 42. During further downward movement of the plunger, the plug cuts a portion or slug of the hot metal surrounding the aperture 17, which slug is dropped through the passage or bore in the die. The plunger is then raised leaving the plug in the cap, which may then be removed. from the apparatus and replaced by another cap. As the caps with the plugs inserted therein shrink, due to cooling, it will be obvious that the plugs Will be very tightly grasped by the crowns of the caps. Upon raising of the punch, the spring 42 moves the sleeve 38 into the position shown in Fig. 5, to receive another plug.

The method of inserting the plugs into the caps is very economical and efficient since no machining operation of any kind is required to secure the plugs in the caps. Also, if the insertion of the plug is efiected immediately after the spinning operation, there will be enough heat in the metal of the caps to permit the cold plugs to form the apertures in the crowns of the caps in which the plugs are then seated.

It will be understood that various changes in the details, materials and arrangements of parts, which have been herein described and illustrated.

in order to explain the nature of the invention, may be made by those skilled in the art, within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. A method for use in making a valve protector cap, comprising heating a length of metal tubing to render the same readily workable, spinning one end of said tubing while hot to partially contract the same to form a crown having an opening in the axial portion thereof, pressing a plug of cold metal of larger diameter than said opening into the portion of said crown about said opening while the metal of said crown is still hot, and simultaneously removing by means of said plug some metal of said crown adjacent to said opening to form a new opening into which said plug fits, said crown upon cooling contracting about said plug to secure the same in place in said crown.

2. A method for use in making a valve protector cap, comprising heating a length of metal tul ing to render the same readily workable, spinning one end of said tubing while hot to contract the same to form a crown having an opening in the axial portion thereof, placing said cap into operative relation to a die having an opening larger than the opening in said crown, with said opening in said die coinciding with the opening in said crown, and pressing a metal plug while cold and while substantially coaxial with said opening in said die, into said crown while the same is hot and cutting from said crown by means of said plug a metal slug of approximately the diameter of said plug, and leaving said plug in the opening formed by said plug, to be gripped by the metal of the crown upon contracting, due to cooling.

3. A method for use in making a valve protector cap, comprisin heating a length of metal tubing to render the same readily workable, spinning one end of said tubing while hot to partially contract the same to form a crown having an opening in the axial portion thereof, placing said cap into telescoping relation toa die having an opening larger than the opening in said crown with the opening in said die substantially concentric with the opening in said crown, releasably attaching a cold metal plug to a plunger reciprocable substantially coaxially with said die,

and pressing said plunger and the plug mounted thereon toward said die while said crown is still hot and simultaneously cutting by means of said plug a slug of metal surrounding the opening in said crown to form in said crown an opening into which said plug fits snugly, and leaving said plug in said opening to be gripped by the metal of said crown when the same contracts, due to cooling.

4. Apparatus for inserting a plu into a protector cap, including a die formed to extend into said cap and having a central passage therein, means for positioning said cap relatively to said die, a punch formed to reciprocate relatively to said die while arranged coaxially with said passage in said die, a sleeve extending about said punch and slidable lengthwise of the same, spring-pressed detents on the lower portion of said sleeve for releasably supporting a plug thereon, said punch when moving toward said die forcing said plug out of engagement with said detents to cut a slug of material from said cap, said punch when movin away from said cap leaving said plug in the aperture formed by said plug when cutting said slug, whereby contraction of the metal of the cap due to cooling of the same will grip said plug.

5. Apparatus according to claim 4 and including means for urging said sleeve into a position in which the lower portion of said sleeve extends beyond the lower end of said punch to enable said detents to receive a plug, said punch when positioning said plug in said cap moving past the lower end of said sleeve for moving said plug out of holding engagement with said detents.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 513,655 Schoen Jan. 30, 1884 1,679,408 Davis Aug. 7, 1928 1,686,562 Jackson Oct. 9, 1928 2,177,191 Sandberg Oct. 24, 1939' 2,309,181 Franck Jan. 26, 1943 2,329,770 Knox Sept. 21, 1943 2,405,201 Franck Aug. 6, 1946 2,406,059 Burch Aug. 20, 1946 2,419,862 Wales Apr. 29, 1947 2,431,537 Bogoslowsky 1- Nov. 25, 1947 

